Good afternoon from Southern Connecticut Weather! 

The winter forecast has been released, December is almost here, and the holiday season is in full swing. We're watching a big storm to start the work week and a gradual pattern change that should make things feel more wintry as we progress through the first week of December. Let's dive in. 

Above is the latest update on precipitation in the region, and the departure from average. As you will see, a good portion of the state is actually within striking distance of a normal precipitation November. Tomorrow's storm should get most places there. 

Monday
A storm is already brewing in the south, and it will quickly develop over the course of our Sunday and cut to our west on Monday. The airmass is already well too warm for any ideas for wintry precipitation here, but there could be a solid early winter storm in parts of Ohio, PA, and western NY. For us, we're looking at rain and wind, and both could be significant at times. 

Above is the NAM high resolution depiction of the storm tomorrow. Rain looks to begin in the morning hours and continue through the day with rain heavy at times. What you don't see here is the wind depiction, which looks quite windy for much of the state, especially southern CT, from late morning through at least the early evening hours. 

Tomorrow looks like a washout with periods of heavy rain. I think a widespread 1-2 inches of rain is a good bet. The wind situation looks robust as well, with inland areas seeing maximum wind gusts of 40-50mph and 50-60mph along the shoreline. Note that areas in SE CT could see the strongest winds and they could be higher than this. I do expect wind advisories or high wind watches to be issued later tonight.

Although it will be windy, with leaves down we're not expecting a major impact with the wind. We should see scattered power outages in the usual spots but I don't think outages are widespread statewide. The rain should end during the early evening hours.

Tuesday-Friday
Although the worst of the weather will be on Monday, there could be some residual showers on Tuesday and as colder air filters in on Wednesday, maybe a few snow flurries in northwest CT. I don't expect much from either, but Tuesday would be a good day to have an umbrella handy. Although Monday and Tuesday look warmer than normal, we're colder than normal on Wednesday with highs in the low to mid 40s. 

Thursday and Friday look great, with more seasonable temperatures and mostly sunny skies. By this time we're watching our next potential system for the weekend. 

Above: Euro (left) and GFS (right) depictions on next weekend's potential storm. Both look like rain at the moment. 

Saturday-Sunday
The weekend is looking unsettled. Another storm system has been showing up on all the guidance for this time frame, and it does look like something will develop. The airmass doesn't look cold enough at this time to support snow (but probably cold enough to keep us in the 40s), but it is something we'll be watching

Longer Range
If you read our 2020-21 Winter Forecast yesterday, you would have noted that we're expecting a pattern change. It will happen in a few stages. First, we will see ridging out west create troughing in the east, bringing cooler temperatures. It won't be enough for significant departures but it's necessary to allow Canada to reload some colder air. The first week of December as you can tell isn't looking terribly wintry, but slowly, we'll be progressing toward a more conductive pattern for colder conditions and some possible activity later in the month. 

The Dailies
Monday: Mostly cloudy with rain and windy conditions. Rain will be heavy at times. Highs in the upper 50s to low 60s. Chance of rain 100%. 

Tuesday: Mostly cloudy with a chance of showers. Highs in the mid to upper 50s. Chance of rain 40%. 

Wednesday: Partly sunny. Highs in the low to mid 40s. Chance of flurries 10%. 

Thursday: Mostly sunny. Highs in the mid to upper 40s. 

Friday: Mostly sunny early with increasing clouds. Highs in the mid to upper 40s. 

Saturday: Mostly cloudy with a chance of rain. Highs in the mid to upper 40s. Chance of rain 30%.

Sunday: Mostly cloudy with a chance of rain. Highs in the upper 40s to low 50s. Chance of rain 20%. 

A​s always, please like, share, and interact with us on our social media--on Facebook to share our discussions, and follow us on Twitter @southernctwx to retweet our posts. Hit the buttons below to join.

Thank you for reading. 
​
-DB​ ​

Hello and welcome to the 2020-21 Southern Connecticut Weather Winter Forecast!
 
Introduction
It’s that time of the year again! Fall is winding down and meteorological winter, which begins on December 1 and lasts until the end of February, is just about here. That means it is time for the SCW Winter Forecast. Our forecast is based on the major factors that influence the synoptic (large-scale) pattern and the weather in our backyard. As we’ve found among our readers, there is a sharp divide between those that like a cold and snowy winter and those that prefer the opposite! 
 
This forecast will examine the key elements that will determine the progression, length, and severity of winter 2020-21. We weigh these elements differently to develop our final forecast. Below you will see our analysis for each. 
 
Now, before we begin, we must add a caveat. It’s hard to forecast ten days out let alone three months. There are a number of winter outlooks and each, including ours, should be taken with a grain of salt. There are always parts that will be wrong. This is our somewhat educated guess as to what will unfold this winter. Let’s hope our final grade is an A! 
 
Methodology
When all is said and done, our final grade will rise and fall on these factors below. Each figure differently in our overall thoughts.  

• Seasonal models (10%): These models are longer range versions of some of the global models we use for short-range forecasting. Here, we look at their composite averages. They have a little skill, but have several distinct biases. We’re not looking at them that much.
  
  
• Analogs (10%): We look at past years that have similarities to this year, whether it be conditions observed during the fall, ENSO state, teleconnections, or previous winters.
  
  
• ENSO (35%): ENSO stands for the El Nino Southern Oscillation, and it represents water temperatures in the central and eastern equatorial pacific. El Nino represents warmer than normal temperatures, and La Nina represents cooler than normal water temperatures. These phases have distinct and outsized impacts upon the larger-scale pattern, and as a result on our sensible weather.
  
  
• Teleconnections (30%): There are many indices measuring current conditions in different parts of the world, from upper level features to regional ocean temperatures. We will discuss the major drivers in the Atlantic and Pacific, and explain what their current and forecast states mean for our weather.
  
  
• Current conditions (10%): This time of year, some parts of the upper level pattern have a strong correlation to what the default weather pattern is during the winter months. We take a look at that here.
  
  

You may notice that we’ve only accounted for 95% of the forecast with the five quantitative factors. The sixth factor, accounting for the final five percent of the forecast, is our gut feeling. Think of it as a best guess on an exam when you may have two right answers in front of you. 

Seasonal Models
Let’s take a look at the seasonal models. There are four of them; the Euro seasonal, the JAMSTEC, the CanSIPS, and the CFS.

A note on how the seasonal models work. Essentially, they attempt to model the upcoming months in much the same way that the midrange global models attempt to model the upcoming forecast period, that is, start with a set of initial observations and apply some physics package to those observations to make future forecasts for the next period on some interval. Then, that forecast is fed back into the model as the initial observations for the next period to be created off of, and so on.
 
As you can imagine, small inaccuracies in initial data or calculations grow exponentially as the recursive cycle continues, and as a result, global models, especially the seasonal ones, are notoriously inaccurate, hence our relatively low weight of them compared to other factors. They are still worth considering and looking at, as what they show (and don’t show) can be valuable when taken in the right context.

First, let’s take a look at the CFS. Here are temperature and precipitation departures from normal on the CFS for December, January, and February, courtesy of weathermodels.com. 

​December

January

February

The CFS advertises an active winter in Connecticut, with above normal temps to start off winter in December and cooling to near normal by February. It also has above-average precipitation all three months, which we’ll see is a recurring theme across some of the other seasonal models.
Next, here’s the Canadian CANSIPS.

The CANSIPS advertises a classic La Nina gradient pattern, with warmer and drier conditions to the south and cooler and wetter conditions in the north. However, the dividing line for both is far to our north, and we are firmly in the warm/dry band on the model. On a monthly basis, December and January are near to slightly above normal precipitation whereas February is very dry, which is also very common in a La Nina where we often see an early start and an early end to winter. Temps are above normal in all three months, with January forecast as the warmest month.
​
Next, let’s go across the Pacific and look at the Japanese JAMSTEC model.

A very similar story to the CFS, and once again showing the classic gradient pattern of a La Nina, at least with the temperature distribution. The gradient is further south here so we are a little bit cooler than on the CFS and much cooler than on the CANSIPS, but still would probably see above normal temperatures. We’d see above normal precipitation as well.

Finally, let’s look at the Euro seasonal.

Once again, above normal for temperatures, and near normal for precipitation. We see some semblance of a gradient pattern when it comes to temps, but the Euro is the warmest of the seasonal models to our north. 

Blending these together, it’s clear that the consensus is for above normal temperatures across the state. All four seasonal models show colder air remaining up in Canada for the duration of the winter and most of the US being flooded with milder Pacific air. While it’s not uncommon to see this gradient pattern set up in a La Nina, typically, one would see the gradient further south, where the northern tier of the US is in the cooler than average temps as well. If you believe the seasonal models, that doesn’t seem to be the case this year. Normally we wouldn’t put a ton of stock in them, but we have been seeing a similar pattern throughout the fall so far – primarily warmer days mixed in with a few shots of below normal temperatures. It’s not unreasonable to expect that will persist as we move into the winter.

That’s not to say that we won’t have cold shots – in fact, we suspect that we’ll see a fair amount of volatility this winter as the gradient shifts back and forth and brings quick shots of colder air with it, but on the whole, it’s clear that the forecast from the seasonal models is for above normal temps. 

Precipitation is more uncertain, with two models having above normal precipitation (JAMSTEC and CFS), one normal (Euro) and one below normal (CANSIPS). Traditionally, the wettest anomalies will be along the temperature gradient from above normal to below normal as storms track along the boundary, and with the temp boundary to our north, one might think the storm track would be less active. However, the models that are suggesting above normal precipitation are implying a pattern with many “cutter” storms, where lows pass to our west and put us into the warm sector, bringing warm temps and heavy rain.

​We’ve seen this pattern develop at times this fall where we see warm and wet systems, and it’s likely that the models are seeing this continue into the winter. All in all, the seasonal models point to near normal to slightly above normal precipitation, but with a lot of volatility and low confidence.

Overall summary of the seasonal models: Above average temperatures and slightly above average precipitation.

Analogs
Each day, the CPC produces a list of analogs that match the upper air patterns over the US. We look for frequent matches and seasons that correlate to what we’ve seen so far as we approach winter, and also use our own observations of the pattern to determine strong analogs. We’ve identified four seasons that share characteristics to this fall: 1995-1996, 2005-2006, 2008-2009, and 2016-2017. The latter two are the closest, so we weigh them doubly compared to the first two.

Seasonal Composites
When you combine all of those analogs, you get seasonal composites that look like this.

Looking at the analogs, we see a fairly classic La Nina gradient pattern for temperatures, with the coolest anomalies in the northwest and warmer air in the south. Connecticut avoids the warmest anomalies but is still about a degree above normal on average throughout the winter.

For precipitation, normal to slightly above normal is shown, with a concentration of wetter anomalies to our west and drier anomalies to our south. This suggests a potential lack of large coastal storms, with the pattern instead favoring “cutters” that pass to our west up into the great lakes before finally moving northeast past our latitude.

These tend to be warm and wet storms for Connecticut. However, there’s also a suggestion for “clipper” type storms given that there is a string of wetter anomalies at around the same latitude from us west to the lakes and even up into Minnesota – the classic storm track for a clipper. These smaller systems can occasionally re-develop into coastal storms (known as “Miller B’s” vs the traditional “Miller A” that comes slowly up the coastline from the Gulf of Mexico) once they hit the Atlantic. This re-development often occurs just south of our area, and, when timed right, can take advantage of a blocking pattern to produce snow. Our suspicion is that if we see a large snowstorm this winter, it will be from this sort of setup.

When looking at the monthly breakdowns, things start to differ a bit. Here they are for temperature and precipitation.

Monthly Breakdowns
​December

January

February

The analogs suggest a quick start and a quick end to winter, with below normal temps and above normal precipitation for December giving way to a warmer and wet January and warmer and drier February. That said, given that January is our coldest month on average, it can still snow in an overall above average pattern. 

Overall, the analogs support the idea of a slightly warmer than average winter with about average precipitation. They suggest an active start to the season before moderating in the back half of the winter, but there will likely still be chances for wintery weather through at least January.

Overall Summary of the Analogs: Above normal temperatures and normal precipitation.

ENSO
ENSO is the big driver of global weather patterns. The significant shift to La Nina conditions helped drive one of the most active Atlantic hurricane seasons on record. As of the mid-November ENSO update by the Climate Prediction Center, La Nina conditions are present and have an approximately 95% chance of continuing through winter. In fact, La Nina conditions may persist into the spring, as there is currently a 65% forecast of that happening.​

Above, you can see the scale of the La Nina so far. As mentioned earlier, a Nina shifts storm tracks further to the north and west, meaning that we are flooded with warm air as a storm approaches, and flooded with warmer air in general as the jet stream stays to the north more often. One thing to keep in mind here is that the strength of an El Nino or La Nina matters quite a bit too. A strong Nina makes it less likely that we stay on track with normal snowfall or temperatures. We will need to monitor the ENSO strength into the winter, but this is looking like a moderate (most likely) to strong Nina event looking at the guidance predictions of ENSO. 

Because this could be a moderate event, we think that unlike past years ENSO will factor in quite a bit more. This should have an impact on teleconnections, as we will describe in the next section, and result in a warmer storm track, more East Coast and southeast ridging, and a much smaller period where traditionally wintry conditions are likely to happen. In keeping with La Nina events, we are likely to see more wintry conditions in the first half of the season, followed by what effectively becomes a quick end to winter. One caveat here is if the Nina is weakening by the end of February and into March, we could see a secondary (albeit small) window for wintry conditions in March. That’s up in the air though. Given how our last few winters have seen wintry conditions...and some of the “bigger” snowfall events in March, we’re going to leave that door slightly ajar in making this forecast. 

Overall Summary of ENSO: Above normal temperatures, normal precipitation, and below normal snowfall.

Teleconnections
The thing you will hear most about during the winter season will be teleconnections. If you’re looking for a short to medium range signal to what the winter potential is, this is it, as teleconnections are essentially the elements of the upper level pattern that determine the orientation of the Jet Stream, location of coldest temperatures, and the activity level (storminess) in the flow. 
These indices measure current conditions at certain placements in the atmosphere, most commonly, the presence of a ridge or a trough. In New England, we place heavy attention to four major teleconnectors--the  AO and NAO in the Atlantic, and the PNA and EPO in the Pacific. 

Arctic Oscillation (AO)
​First, the Arctic Oscillation, or AO. This is an index measuring pressure anomalies in the Arctic, and is strongly correlated with temperatures in our area for the winter months. A positive phase of the AO consists of below average geopotential heights. A negative phase consists of the opposite. In a negative phase of the AO, the polar vortex over the Arctic is weaker, resulting in weaker upper level winds that make it easier for Arctic air to penetrate further south. Another result is a further south storm track. With a positive AO, the opposite is true. Stronger upper level winds keep the polar vortex in check, making it less likely for deep cold air intrusions and ideal storm tracks. This year, the polar vortex (PV) looks very strong, though there are a few signals that it could weaken in the coming weeks. This likely means that it will be more difficult, on balance, to get big and long lasting intrusions of colder than normal air, if the PV stays strong. Even then, that doesn’t mean it won’t be cold at all, it just means that overall things are looking milder unless there is a significant event that weakens the polar vortex. 

Below is an image showing what a strong AO looks like. The image is merely illustrative, but note how the heights are well below average in the polar region. That’s a warm period.

North Atlantic Oscillation (NAO)
The NAO is the North Atlantic Oscillation, and is a close relative of the AO. Here, forecasters look at two pressure centers in the Atlantic--an area of low pressure near Iceland, and a high pressure system near the Azores. Generally, during the winter we’re paying close attention to heights around Iceland. The strength and exact placement of these features tend to have a significant impact on the placement of the jet stream--absolutely critical for cold air placement and storm track in tandem. During a negative phase, we see higher heights over the Iceland area, and below average heights over the western Atlantic and (usually) the eastern US. The opposite generally occurs with a +NAO, which means more progressive tracks and more warmer storm tracks. 
 
While a persistently negative NAO is not necessary for a cold and snowy winter, having a -NAO, even if transient, can be a major factor in producing some of our biggest winter weather events, as a -NAO usually implies more blocking is available, while a +NAO represents a faster pattern with less room for storms to amplify. Further complicating matters is the position of the heights. A west based -NAO is more likely to produce a cold and stormy period than an east based -NAO. A persistent -NAO is far less likely this year given the general ENSO state and strength of the polar vortex region. However, there is an increasing chance we see a negative NAO in December and perhaps a more neutral regime into January. That would certainly not hurt for those on the cold and snowy train. 
 
Again, here's a historical look at a negative NAO from 1966.

Pacific/North American Pattern (PNA)
Although a lot of attention is often given to the Atlantic and NAO, the pattern in the Pacific is vital to determining the course of a Connecticut winter. The PNA is one of the most important teleconnectors, with a significant influence over North America. A positive PNA phase occurs when there are higher heights over the Pacific and western US. This correlates to ridging over the western US and a trough (transporting colder air) over the eastern US. In a negative phase, the opposite occurs.

The position of the western ridge matters quite a bit. Too far west and storms can cut to our west, bringing rainy systems or nothing at all. Too far east and storm tracks could develop too far offshore to bring significant precipitation events. While there is less likely to be a favorable Atlantic pattern, there are some mixed signals on what happens in the Pacific, especially early. We think that there will be a window for a more favorable winter pattern that is driven by the Pacific, most likely in the early to mid winter period consistent with ENSO. Then, we think the door will all but close, pleasing winter haters across Connecticut. 

East Pacific Oscillation (EPO)
Finally, we have the East Pacific Oscillation, or EPO. The EPO is a major driver in allowing Canada to develop cold air that feeds into the US, or shutting off any mechanism to deliver cold to much of Canada or the US. Here, we’re looking at heights over the northeast Pacific and Alaska. Higher heights over this region brings warmer than normal weather over that region, but it serves up an almost ideal mechanism for cold air delivery in the continental US, as a resulting Arctic high in northwest Canada and trough over the US work in tandem to funnel cold into the region. At times, we can see as sprawling enough -EPO to develop what is called “cross-polar flow”. This is the extreme cold that comes straight from the polar region without much moderation. 

On the other hand, with a positive EPO phase, we (potentially) see the worst of what winter can offer if you like cold and snow. In a +EPO, we get a persistent low (vortex) in the northeast Pacific and Alaska, which creates favorable conditions for the dreaded PAC jet to inundate Canada and much of the continental US with warm Pacific air. If you have this kind of pattern persist, you can almost guarantee little cold and snow.

Here's a look at the positive and negative phases of the EPO and their effects on our sensible weather. 

Overall, we anticipate that the teleconnection pattern will provide a 4-6 week window for the bulk of our colder and snowier winter. This pattern is likely to begin flipping in early December, but really take hold between mid-December and mid January. However, after this period it looks like the Pacific may shut down, bringing a quick flip to warmer and less snowy conditions into February and potentially the first half of March. 

Overall summary of the teleconnections: Above normal temperatures and normal precipitation.​

Current Conditions
In the past we looked at snow cover across Siberia to help determine the longer term forecast. Not this year because we don’t think the data is there for a meaningful correlation. 

Here, we’re looking at the current upper level pattern heading into December, as there seems to be a fairly strong correlation between the upper level pattern, especially in the Pacific, and the default pattern during the winter season. Of course, this doesn’t always work. Last year we saw a roaring start to winter, with a favorable pattern and above normal snowfall that flipped and never returned. So we’re looking at this, but with wary eyes. 

The signal has been all over the place for much of November. Just a few days ago, it looked like we would see a Pacific pattern setup that would all but torch much of the US as the month of December begins. Since then, we’ve seen a slow but steady retreat from that idea on the guidance and reversal to a good pattern. That doesn’t mean that we’re going to cold and snowy conditions at the beginning of December, it will take time for cold to load in Canada, which is our source region for cold, but it does make it less likely that December is a torch, which is critical to the overall progression of the winter as the latter half looks unfavorable.

Given current conditions, and the projected conditions as we start December, we think despite above normal temperatures on balance, there will be enough of a window to bring snowfall closer to normal than last year. When looking at the EPS and GEFS below you can see why. The Pacific pattern looks good for cold loading heading into mid-December. 

Overall summary of current conditions: Near to slightly above normal temperatures, fading to normal to slightly below normal temperatures in mid-December. Above normal precipitation. Normal to slightly above normal snowfall (especially late December). 

Gut Feeling
At the end of the day, when there are conflicting signals you have to make a call one way or the other. Although it looks highly likely that we end up with a warmer than normal winter on balance, snowfall and precipitation are less clear. When you are relying on a relatively small window to meet snowfall normals, that creates a lot of ways totals can end much lower than normal. On the other hand, with a period of blocking you can get one blockbuster storm that dominates one’s perception of the season and has an outsized impact on seasonal snowfall totals. 

It’s hard to get less wintry than last season, so we do not believe we will see a repeat of that. However, Connecticut has been in a bit of a streak where winter has been backloaded to March, or hasn’t really produced a normal snowfall season. 

Given the data we have, it looks like mid-December to mid January is most likely to be the wintry period. That doesn’t mean it won’t be cold or snowy at another time, but things look to flip to warmer (maybe outright torch) conditions for February and perhaps the first half of March before we go into another uncertain period where we could see a brief wintry period return. Our gut says we are warm overall, but in that 4-6 week period find a way to get close to normal seasonal snowfall. That likely means at least one significant snowfall event. We should also say that given the La Nina, this could be a gradient winter, where snowfall events and totals have sharp differences in just a few miles due to the warm air that is likely to be lurking for many storms. 

Overall summary of gut feeling: Above normal temperatures, normal precipitation, and slightly below normal snowfall.

The Forecast
To recap, here are the summaries of our six variables that make up the forecast:

Overall summary of the seasonal models: Above average temperatures and slightly above average precipitation.

Overall Summary of the Analogs: Above normal temperatures and normal precipitation.

Overall Summary of ENSO: Above normal temperatures, normal precipitation, and below normal snowfall.

Overall summary of the teleconnections: Above normal temperatures and normal precipitation. 

Overall summary of current conditions: Near to slightly above normal temperatures, fading to normal to slightly below normal temperatures in mid-December. Above normal precipitation. Normal to slightly above normal snowfall (especially late December). 

Overall summary of gut feeling: Above normal temperatures, normal precipitation, and slightly below normal snowfall.

Temperatures
Temperatures are where the highest confidence is found. There are virtually no signals that suggest that we will see a colder than normal winter. In fact, we are inclined to say that each month of the winter period is warmer than normal. We’ll see if next April and May are colder than normal like they were this year, but that’s outside of our forecast period. December and January look to be our coolest months, even as they are above normal on balance. February looks much warmer than normal. March could go either way, but we lean warmer than normal. Again, this is outside of our forecast period. 

Summarizing, temperatures look like this:
December: .5 to 1.5 degrees above normal
January: 1 to 2 degrees above normal
February: 2 to 4 degrees above normal
Winter Composite: 1.5 degrees above normal to 3 degrees above normal

Precipitation
With regard to precipitation, there isn’t a whole lot that suggests that we go back to the drought conditions we saw much of the year, especially during the summer. The signals are mixed as to whether we see above normal precipitation or normal precipitation but overall it’s probably not going to matter too much because if we are wetter than normal it’s not likely to be by much. This is consistent with La Nina, but also with having a period with favorable teleconnections for stormy conditions, whether they lead to wet or white. Our thought is that December and January determine whether we go above normal or not, while February is warm and dry. 

Here’s the forecast for precipitation:
December: 100% to 120% of normal
January: 90% to 120% of normal
February: 50% to 75% of normal
Winter Composite: 90% to 110% of normal

Snowfall
Now for what you’ve been waiting for. Nobody really cares if we are off on the amount of precipitation or temperatures. It is snowfall that dominates our perception of winter. Last year we were off to a blazing fast start in the snowfall department before it ground to a halt and never really picked up until we had a March event that boosted very low totals. In addition, it was also a gradient year, where there was a massive difference between shoreline locations and central Connecticut, and central Connecticut and northern Connecticut. That makes a snowfall forecast difficult as well. Central and northern Connecticut are most likely to see a normal snowfall winter, but even here, things are tricky. We are really depending on a large enough window in December and January to offset what we anticipate will be an early start to spring. 

With a less active southern stream we are likely to see storm tracks that are mostly to our west or close enough to introduce mixing problems. Clippers and Miller B systems are forecasted to be our most common storm track. 

December: 120% to 140% of normal
January: 100% to 120% of normal
February: 25% to 50% of normal
March: 80% to 100% of normal

Winter Snowfall: 75%-100% of normal, with the highest chance of normal snow in the NW hills and northern CT.

We think this is one of those winters with something for everyone. For winter weather lovers, the earlier start to winter means that we could have chances at significant snow events during the holiday season and just after. For those that dislike wintry weather, we could see an early start to spring, and warmer temperatures in February/early March. The state as a whole will likely see a rollercoaster winter, starting out relatively strong in our 4-6 week period before falling back during a warm and dry February. That will leave March as the wildcard. 

The Winter Ahead
SCW has grown to over 24,000 followers and we are humbled by the opportunity to forecast for you. As you are already seeing, we are working to update our website to make the page more accessible for you.

This is our busy season, and we’re ready to have another good season of no-hype forecasting and grading ourselves after significant events. Maybe we will have a few surprises too along the way. 

You can also follow us on Twitter @southernctwx for information on advisories, models, and news and on Facebook for continued high quality analysis, including model interpretations and quick thoughts.  
​
Thank you for reading and trusting SCW. Please continue to like, share, visit our website, and encourage others to do the same. 

-SCW Team

Disc: We'll have a warm next 5 to 7 days, but just as the calendar flips into December, a much more wintry pattern looks to take hold.

Currently: Sprawling high pressure from NC to PA up into QC.  A dying cold front was located over the Hudson Valley.  Other than a few clouds, this cold frontal passage will be unremarkable.  

Tonight: Clouds increase, so low temps probably occur in the 1st part of the night.  Therefore, I went a few degrees above guidance.  Expect lows ranging from the mid 30s in the NW hills to 40-45 S coast and urban areas.

Tomorrow: Generally mostly cloudy, but we'll stay dry.  Clouds should negate warm air advection, as far as temps go, so no real reason to change guidance too much.  Expect high temps of 50-55 degrees.

Thanksgiving: Looks like a rainy Thanksgiving day is in store for the area.  It should be raining by dawn across the entire state.  There should be something of a dry slot progressing SW To NE across the state, from early aftn SW CT to mid aftn NE CT, then a line of showers and possibly even t-storms later in the afternoon into the evening from SW To NE.  Due to clouds and rain, I went a few deg below guidance.  So xpct highs in the mid to upper 50s.

Long Term: Most of the action in the long term will be centered around a storm moving up, inland, from the E coast on Mon.  

First, for Friday, although a cold front is going thru T-day evening, there isn't much cold air behind it, due to the air mass being of Pac origin.  Therefore, Friday will not be cold at all.  Due to the fact that I can't see any reason to improve on guidance, I went with it.  Expect highs in the mid to upper 50s.

For Saturday, a weak impulse moves through during the day and could touch off a weak sprinkle or light rain shower.  Due to the fact that this is Day 4, and I don't like to put pcpn in the fcst if widespread measurable is not xpctd beyond Day 3, I have left Sat dry. However, there is the chance for sprinkles or light rain showers at just about any time during the day.  Again, I don't really see any reason to tweak guidance, so expect highs close to guidance- in the 50-55 deg range.

Sunday should be fair, although clouds should increase later in the day, ahead of the next sys.  Highs should be near 50 degrees, which again is relatively close to guidance output.

Now for Monday, a large storm system will impact the area.  Consensus track has it going west of us- probably something like up the Delaware then Hudson River valleys.  Given the expected storm track, all pcpn at this point should be liquid, at least in front of the storm.  There is some question as to how long the storm will be or how strong, and this depends on phasing, with the Canadian model continuously being the most aggressive with phasing.  For now, for lack of trying to be too cute, and the fact that it does look like an all-day event, will just go generic "rain" for Monday.  Depending on the exact track, the chance of thunderstorms is non-zero.   However, I don't want to put t-storms in a day 6 forecast at the end of Nov.  Out of an abundance of caution, I stayed close to temp guidance, which is 50-55 degrees, but I could see it ending up a few deg warmer.

This is also uncertain, because it is related directly to the track of the low and what exactly it does when it leaves the area, but there could be instability showers Tue morn, and as colder air filters in, those could turn over to sleet or snow, but I am not expecting any accumulations or anything like that.  Either way, Tue should turn much colder.  Due to strong CAA that numerical guidance almost never recognizes this far out, I went well below temp guidance on Tue, and will only call for highs in the low 40s.  

The long range looks cold and looks like it could be quite the wintry pattern setting up for the area.  Details on individual storm tracks and impacts for the region obviously remain up in the air, but the pattern does look to be setting up into a wintry one!

Now let's take a look at some of the systems set to affect the area over the next week.  First, let's take a look at the Thanksgiving storm, then we'll look at Monday's storm.  Looking at this map, expect a rainy Thanksgiving.  You can see rain over the area, and much lighter shades, our break, over PA.  What is out near Cleveland and likely to swing thru later is our t-storms.

Here is a map valid Monday midday.  At this juncture, what more can I say other than looks like a rainy Monday?

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That's all for now! Take care and have a Happy Thanksgiving!

​-GP!

Good afternoon from Southern Connecticut Weather! 

It is a cloudy and cool day in Connecticut as our next storm approaches. Unfortunately, the forecast for Thanksgiving Day, where a lot are hoping to be outside, is looking less than ideal. Let's dive in. 

Above: the temperature departure from November so far. Although we've had some cold periods, overall we're still above normal by quite a margin.

Sunday-Monday
It is mostly cloudy in CT today, but there are already some showers around. We should see an increase in coverage of the rain showers late today and especially this evening as an area of low pressure travels well to our northwest. This storm system should bring us some meaningful rain, which is still needed given our continued rainfall deficit. The rain should be heaviest overnight and tomorrow morning, but conditions will only slowly improve over the course of our Monday and rain may be heavy at times. It should be breezy nonetheless. Tomorrow looks warmer than today as warm air is advected in ahead of a front that will deliver a colder Tuesday. 

Tuesday-Wednesday
​Tuesday should be beautiful as high pressure builds in and brings sunny but breezy conditions as colder air advects in. Highs will be in the low to mid 40s, though some hill towns may top out in the upper 30s. Wednesday should be dry and slightly warmer, but clouds will be increasing as our next storm system approaches. 

Thanksgiving Day
Turkey day is looking wet. Another area of low pressure is expected to traverse the region and it will complicate Thanksgiving plans. Right now, there is a bit of uncertainty in the timing and intensity of the storm. Rain showers look to begin during the pre-dawn hours of Thursday. That's also when we may see the heaviest rain. There are mixed signals on how quickly the storm will depart. The GFS for instance only has light showers during the afternoon. The Canadian has a stronger storm that washes out the day. The European is kind of in the middle, with heavier rain in the morning hours and some showers in the afternoon, heavier than the GFS but not a washout like the Canadian. 

Right now, I think outdoor activities on Thanksgiving look tough. Although temperatures will likely top out in the upper 50s to low 60s, there looks to be enough precipitation around that only those with covered patios are likely to have a decently comfortable outside gathering. This forecast will need to be fine tuned, so expect more from us as we get closer to Thursday. 

Above: depictions of Thursday afternoon on the Canadian (left) and GFS (right). There's still quite a bit of difference on the guidance but overall Thanksgiving is not looking good for outdoor activities. 

Friday-Sunday
The period after Thanksgiving starts out quiet, but by the weekend we may be looking at more unsettled weather. First, Friday looks nice as the Thanksgiving storm moves out. Conditions should be partly cloudy with seasonable temperatures. Saturday we are back to cooler temperatures, increasing clouds, and a chance of showers as the guidance is nearly unanimous on a big storm developing to our south and west. This should be a rain event, but the timing is all over the place right now. At the moment, Saturday looks ok, but Sunday and/or Monday look to bring rain and breezy conditions. 

The Dailies
Monday: Mostly cloudy and breezy with rain. Highs in the mid to upper 50s. Chance of rain 80%. 

Tuesday: Mostly sunny and breezy with cooler conditions. Highs in the low to mid 40s. 

Wednesday: Increasing clouds. Highs in the upper 40s to low 50s. 

Thursday: Mostly cloudy with rain and rain showers. Highs in the upper 50s to low 60s. Chance of rain 60%. 

Friday: Mostly sunny. Highs in the mid to upper 50s. 

Saturday: Increasing clouds with a chance of showers. Highs in the low to mid 50s. Chance of rain 30%. 

Sunday: Mostly cloudy and breezy with a chance of rain. Highs in the upper 40s to low 50s. Chance of rain 40%. 

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Thank you for reading. 
​
-DB​ 

Disc: The bitter cold air mass is getting flushed out of the region- to be replaced by warmer temperatures, but that too, will be fleeting.

Currently: Sprawling high pressure extends from KCLT to well offshore.  This high will translate offshore overnight and set up a return flow of warmer air for the next two days.

Tonight: A much warmer night across the area.  I don't think we radiate all that well as bands of cirrus clouds continue to streak into the area.  For that reason, I went close to guidance and did not undercut as I would normally on a radiative night.  Expect lows from 30-35 in the NW Hills to the low 40s along the S coast.

Tomorrow: It is unclear exactly how sunny it will be, especially in light of today.  Today was forecast by nearly all models to be mostly sunny and is verifiying partly to mostly cloudy.  Therefore, I went just close to, or just below, temp guidance with uncertainty in cloud cover.  Still, it will be much warmer, with highs in the mid to upper 50s.

Tomorrow Night/Sat: One more day of above normal temps on Sat.  Forecast reasoning and methodology is the same as Fri.  Once again, uncertain of how much sun we actually get vs. modeled, so went close to, or just a smidge below guidance.  Expect temps in the upper 50s for highs.

Forecast confidence decreases a bit heading into Sun.  For now, will keep the day dry, but there has been a discernable trend towards faster with this system.  Either way, Sunday should see increasing cloudiness and turn more "raw" as high pressure up N presses cooler air into the region.  I went way below guidance on Sunday's highs, due to clouds and strong NE flow.  Temps probably don't rise much from AM lows.  Xpct highs in the mid 40s.

A shot of light rain is likely Sunday night into early Monday, perhaps even ending with a burst of moderate rain.  This may linger for a few hrs Mon morn, otherwise expect clearing skies on Mon.  Temp guidance looks very warm to me for Mon, esp given that a) we may not clear until the 2nd half of the day and B) there is cold air advection.  Therefore, I went quite a bit under guidance.  Temps may very well just hover in the low to mid 40s from Sat night to Mon afternoon.

For Tuesday, I largely went very close to temp guidance, or just a smidge cooler here and there.  Good cold air advection in place, if only temporary.  Clouds begin to increase by nightfall ahead of the next system.  Temps once again should be in the 40-45 degree range.

A large and moist system is slated to affect the area the day before and Turkey Day.  Right now, the evolution looks something like one low driving up into PIT and another forming offshore.  In complex situations like this, a lot of questions generally arise, such as how far north the primary low gets before transferring its energy and where exactly the coastal low begins to bomb out.  Unfortunately, from this distance in time, there tend to be more questions than answers.  For now, expect unsettled wx most, if not all, of Wed, and at least part of Thu, until we get closer and can hone in on the details.

It should be noted that the GGEM (Canadian) model is very different in evolution with this system. showing light, overrunning rains early on Wed, then a break, and then heavier rain on Turkey Day as a low moves straight up the Del River.

The ECMWF seems to be an outlier, with no overrunning moisture at all on Wed, then has the low track basically over NJ on Turkey Day, which is similar to the GGEM solution.  Bottom line, expect unsettled wx those two days.

Because my solution is a bit faster than a model avg, I went wamer than guidance on Wed and cooler on Thu.  This would be reflective of a quicker warm surge, but also quicker cold air advection.  This would yield highs of 50-55 Wed and near 50 Thu.  It should be noted that refinements are likely in this forecast until "game time".

There could be more unsettled wx the weekend after T-Day, with the GFS showing a coastal developing from a clipper.  There is cold air in place, but the coastal develops too late for anything but maybe some flakes mixing in.  In that setup, earlier development could result in snow.  The GGEM is also showing a storm, but is slower and stronger, in that the low develops very near the NJ coast.  This results in heavier precip, but a warmer solution and definitely all rain.  Meanwhile, the ECMWF holds the energy back over TX and basically says what storm? Given that that is an outlier and the ECMWF is biased toward holding energy back, that solution will be ignored.  Prepare for more unsettled wx that weekend!

Now, let's take a look at systems expected to affect the region using graphics.  I'll show Monday morning's light rain and the potential Thanksgiving storm.  For the Mon morning rain, you can see, this rain is propagating NE, and most of it misses CT to the N or NW.  However, there is a shot of steady light rain that does make it to the area.  

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Now for the Thanksgiving system, a low pressure system that strong over Orange County, NY, would surely produce heavy rain over our area, and is modeled here.

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Anyway, that's all for now! I'll prob see you some time next week!

​-GP!